(1) Field of Industrial Utilization
The present invention relates to a controller for electric power distribution apparatus in which an interlock condition among lined apparatus is improved.
(2) Description of the Prior Art
Generally, electric power is supplied to loads from electric power companies. But, when a power failure is caused by an accident, such loads which are necessitated to prepare for a long time power outage as hospitals, computer power sources etc. switch over a power source from the electric power company to private power generation. A controller for electric power distribution apparatus having interlock conditions is used for the switching over the power source from electric power company to the private power generation.
The interlock condition is so settled that power supply from the private power generation is absolutely prohibited when power is being supplied from the electric power company. Reversely, power supply from the electric power company is absolutely prohibited when power is being supplied from the private power generation.
The controller used in the above described case is such an apparatus having control lines among a plurality of distribution apparatus and control distributing lines which are connected in parallel between the control lines of positive side and the control lines of negative side. The control distributing lines are arranged to each distribution apparatus. The control lines connect such interlock switches as operation switches and closing coils having the interlock conditions.
The interlock switch connects, for example, a contact point which operates the closing coil at the electric power company side to, for example, the control distributing line at the private power generation side, and also connects a contact point for the closing coil at the private power generation side to the control distributing line at the electric power company side. Accordingly, when the closing coil at the electric power company side is excited, the contact point of the closing coil at the private power generation side keeps opening, and electric current does not flow to the control distributing line. Such control circuit as above described is disclosed in, for example, JP-A-63-178737 (1988).
In accordance with the above described prior art, there is a disadvantage that power failure is caused when an accident is generated in the control distributing line at the electric power company side, because electric current does not flow to all of control distributing lines at both the electric power company side and the private power generation side. The above described disadvantage is typical of all closed type distributing apparatus, There is another disadvantage that all of the distribution apparatus cause power failure when some of the distribution apparatus are additionally installed because the control distributing lines are mutually wired in a plurality of distribution apparatus.